The invention relates to an apparatus for introducing bulk goods into a container, the apparatus having an arrangement for extracting dust, which can pass into the surroundings during filling of the container, by suction. The invention also relates to a process for using an apparatus according to the invention.
Various apparatuses for introducing bulk goods into containers are known from the prior art. Relevant apparatuses in the present case are those which are suitable for dust-containing bulk goods or for bulk goods in which dust may be produced, for example, by abrasion during transfer.
Open ventilator cowls, which are arranged above the filling location, are known in general.
DE 42 11 855 A1 describes an arrangement for loading bulk goods. In one embodiment, a dust-removal nozzle is provided in the region where the bulk goods enter the loading arrangement. A dust-return line results in dust-laden air being returned from the container which is to be loaded into the loading hopper of the loading arrangement. During operation of the arrangement, the dust within the loading arrangement is directed to the dust-removal nozzle by way of the air stream, a negative pressure being present in the interior of the arrangement. During loading of the bulk goods, the arrangement is coupled with dust-sealing action to the container which is to be loaded. In this case, the hopper mouth and the dust-return line are introduced in parallel into the opening of the container which is to be loaded.
DE 72 18 354 U1 describes a loading arrangement for loading silos with bulk goods in a dust-free manner. The loading arrangement has a filling tube, of which the bottom end is enclosed by a rubber-coated loading cone. The loading cone, which is arranged in the form of a ring around the filling tube, simultaneously serves as a dust-removal nozzle, which is connected functionally to a suction-extraction and dust-removal apparatus via a folding bellows. During the sealing operation, the loading cone is seated firmly, in a dust-sealed manner, in the introduction hole of the silo.
The disadvantage here is that it is not possible to prevent at least some dust from escaping into the surroundings, or relatively high-outlay sealing of the hopper mouth and of the dust-return line in relation to the opening of the container which is to be loaded is necessary. It is also disadvantageous that coupling the arrangement and the dust-return line to the container which is to be loaded results in connecting forces taking effect, as a result of which it is not possible for the net filling quantity to be determined precisely during filling.
It is thus an object of the invention to specify an apparatus for introducing bulk goods into a container of the type mentioned in the introduction which prevents dust from the bulk goods from entering into the surroundings. It also intended to specify a process for using the apparatus. It is also intended to be possible here for the net filling quantity to be determined precisely during introduction of the bulk goods into the container.
The invention achieves the object in respect of the apparatus by the features mentioned in the defining part of claim 1. Advantageous developments of the apparatus are defined in subclaims 2 to 6 and are illustrated in more detail hereinbelow together with the description of the preferred configuration of the invention, including the drawing.
The object in respect of the process is achieved by the defining part of claim 7. An advantageous development of the process is defined in subclaim 8.
The essence of the invention consists, in particular, in that the apparatus has a housing, of which the interior is connected to an external arrangement for extracting dust by suction, in that the sealing tube is mounted within the housing, and in that air-inlet openings are provided in the housing radially outside the introduction housing of the container which is to be filled.
In the case of the process-related use of the apparatus for filling a container with bulk goods, the apparatus, specifically the filling side of the housing, is positioned above the container, i.e. above the introduction opening of the latter, such that a defined gap is produced between the housing and the container. In respect of the process, it is further the case that the arrangement for extracting dust by suction is set in operation.
The arrangement for extracting dust by suction produces a negative pressure in the housing of the apparatus, which results in air from the surroundings flowing into the housing, by way of the air-inlet openings, on the filling side. A collar is advantageously arranged on the filling side of the housing, radially outside the introduction opening of the container and the air-inlet openings. In the filling position, this collar is intended to project axially beyond the outer border of the introduction opening. As a result, the air stream is deflected essentially in a vertical direction and swirling of the air, which possibly results in dust passing into the surroundings, is avoided.
The air stream flows around the introduction opening of the container in tubular fashion. This results in all the dust particles and gases escaping from the container during filling of the latter being entrained. The escape of dust from the gap between the apparatus and the introduction opening is more or less prevented by the air stream.
In an advantageous configuration, the filling tube is arranged such that it can easily be removed from the housing. For this purpose, the filling tube is mounted in the housing, and sealed in relation to the latter, by means of rubber sleeves. This reduces any vibrations in relation to the apparatus during the bulk-goods transfer. The filling tube can easily be drawn out of the housing.
This is advantageous, for example, if the apparatus is to be used for transferring different bulk goods, using different filling tubes, at successive points in time. In particular in the case of pharmaceutical bulk goods, e.g. powder or granules, it is necessary from a technological point of view for the entire apparatus to be cleaned cyclically. For this purpose, it is necessary for the apparatus, including the filling tube, to be dismantled and fed to a washing apparatus.
The actual design of the housing with the filling tube and air-guiding means can be varied to a great extent and adapted to the geometrical and structural conditions.
When the apparatus is in the rest position, i.e. when there is no container which is to be filled positioned beneath the apparatus, it has proven advantageous to arrange a protecting means beneath the housing and, in particular, beneath the outlet opening of the filling tube. This prevents residues of the bulk goods from trickling accidentally into the open from the filling tube, or prevents dust deposits from dropping out of the filling tube and contaminating the surroundings.
The extent to which it is necessary to allow the arrangement for extracting dust by suction to function even when the outlet opening of the filling tube is actually closed is determined by the actual technological conditions.
Protecting means which may be used are slide-like, shutter-like, pivoting-plate-like or iris-diaphragm-like means, as are known in general from the prior art. The selection in practice is decisively influenced by the local conditions. The protecting means is advantageously mounted in a dedicated housing. When not in use, it can be retracted into the housing. It is possible here to provide in the housing special suction slots, by means of which any residues of bulk goods present are extracted by suction during retraction of the protecting means.